The film's approach to these parties, and to the self-destructiveness and promiscuity they promote, is at once disapproving and fascinated, and it is much to Mr. Shafer's credit that this seems less a mark of hypocrisy than of honesty.

Like John's cousin Tad (Daniel Kucan), a filmmaker shooting a video documentary about the men of the circuit, Mr. Shafer explores this world with a sympathy and a curiosity that balance his worries about its emptiness and danger. For all of its lubricious attention to naked and half-naked male bodies, all of them impeccably muscular and smooth, ''Circuit'' is ultimately more sorrowful than exploitative.

At first, John keeps his distance from the circuit's perilous pleasures. ''I don't need that stuff to have a good time,'' he says when someone offers him the latest designer party drug. But he isn't having a very good time, and soon, accompanied by a hustler named Hector (Andre Khabbazi), he is injecting steroids, inhaling all kinds of stimulants and losing his grip on stability.

Tad's ex-boyfriend Gill (Brian Lane Green), and John's roommate, Nina (Kiersten Warren), an old flame from home chasing her own Hollywood dream, try to intervene, but the illusion of freedom, of life as an endless succession of parties, is powerful indeed. Meanwhile, several subplots probe the corrupt underside of this night-life paradise, which is organized by an unscrupulous (and heterosexual) impresario named Gino (William Katt).

''Circuit,'' which opens today in Manhattan, San Francisco and San Jose, Calif., is hectic and overlong. Both the screenplay, by Mr. Shafer and Gregory Hinton, and the finished movie would have benefited from more rigorous editing. Some of the actors, including Mr. Drahos, seem awkward and adrift, and the nonparty, nonsex scenes are often plodding and expository. But there is a real subject here, and it is handled with intelligence and care.

Mr. Shafer seems to be trying to update the sympathetic critique of gay male sexual culture that Larry Kramer offered 25 years ago in his novel, ''Faggots'' -- to take hedonism seriously as a mode of self-discovery while suggesting how hazardous too single-minded a devotion to pleasure can be. A. O. SCOTT